The last image is a different strain that is actually doing really well. The 1st photo was doing the worst. These are about 5wks into veg and still no roots coming out of the blocks???? These photos are from today. The plant that a was doing poorly is now basically a lost cause. So my question is, overwatering?
There are in 2x4 trays, 16 per tray under 400w of T5 lighting.I have been hand watering them every few days. I have other strains in other tables that are doing great, getting the same treatment and food. Which is H&G Aqua Flakes at appox. 800ppm ph of runoff is 6.0.
I should add, the other trays that are doing much better have massive root structures coming out (well, they died back a bit because they sat in some water too long). I was thinking maybe I should put them on a drip system and stop handwatering?
The trays are not plumbed for drainage, but I have been just giving them 500ml of water at a time so, usually it stays in the channels and the blocks themselves are not sitting in water. Though that did happen with one tray, the roots died back but those plants are looking great overall. The tray I am having trouble with has never sat in water, but never really put out roots, they have been topped and are about 8-10" tall now.
Looks like mad over watering combined with some salt building up.
I would flush with florakleen from top down, then empty the trays they are sitting in and let them dry completely.
Slow, molted growth is a sign of over watering. They may even be close to root rot in the cube, in which case I would flush with 2ml/gal H2O2 after the florakleen.
Go by weight with rockwool, its very easy to know when they dry out, they are feather light...
my 2 cents
T
PS: algae on top indicates too much top feeding, if you continue to top feed, use block covers, I bottom soak mine to avoid this problem without using block covers.